Williams, who is aiming for a 16th grand slam triumph next month after winning Wimbledon and the U.S. Open in 2012, is among eight of the world's top-10 women competing in Brisbane.

First-round matches start on Sunday, and tournament organizer Cameron Pearson is delighted that both Sharapova and Williams will be present along with world No. 1 Victoria Azarenka.

"I think Maria and Serena are the two biggest stars in women's tennis so it's great that they're both going to be here and both be fit and ready to play the first tournament of the year," he told Australian media.